Clamshell dredge



Sept. 6, 1938. J. c. WILLIAMS CLAMSHELL DREDGE I5 Shets-Sheet 1 Filed Aug. 3, 1936 ZNYENTUR- Z4 44%;?

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Sept. 6, I938. J. c. WILLIAMS CLAMSHELL DREDGE Filed Aug. 3, 1936 5 Sheets-Sheet 5 Patented Sept. 6, 1938 UNITED STATES CLAMSHELL DREDGE John (3'. Williams, Oakland, Calif., assignor to John C. Williams Corporation, a corporation of Nevada Application August 3, 1936, Serial No. 93,971

18 Claims.

This invention, a clam-shell dredge, combines in a single unit, a clam shellbucket and its operating means and prime mover, and is particularly intended for submarine dredging for recovering values from the ocean and river bottoms; there being known areas in the depths of the ocean and deep rivers where large values in gold and other precious metals exist, and which can be recovered, provided the precious metal-bearing sand, silt or sludge can be brought to the surface and retained against washing out of the recovery means while being hoisted to. the surface through the water, and provided the recovery means or dredge can be operated at great depths.

This invention is particularly designed for this specific purpose, though it can as readily be used under any conditions, in or out of Water, and where there is suificient depth, the dredge is selfoperating, requiring only a hoisting cable for 20 raising and lowering the dredge, and manual control means for dumping the dredge when it has reached the surface.

The objects of the invention are as follows:

First; to provide a clam-shell bucket with integral operating means including a prime mover.

Second; to seal said prime mover against fluids under high pressure.

Third; to seal the clam-shell bucket against loss of fine material, such as sludge, while the 30 bucket is being hoisted to the surface.

Fourth; to provide such sealing means with internal pressure, and maintain the value of such pressure greater than the value of the pressure of submergence, to maintain a perfect seal irrespective of the depth of submergence.

Fifth; to provide automatic control means for controlling the closing of said bucket, and manual control means for controlling the opening of said bucket.

Sixth; to provide automatic control means which will operate only when a predetermined depth of submergence is attained or a subsurface is reached.

Seventh; to provide a prime mover for submersible devices which is operated by the presture of submergence.

Eighth; to provide a dredge as outlined which will automatically close, seal and lock, when lowered to a predetermined depth or surface, and remain locked in closed position until manually released.

Ninth; to provide a static-fluid operated and controlled prime mover.

Other objects and advantages of the invention will become apparent as the following description is read on the drawings forming a partof this specification, and in which similar reference characters are used to designate similar parts throughout the several views, of which:

Fig. 1 is a vertical section through one form of the invention, with the bail removed, and is taken substantially on line L-l of Fig. 2.

Fig. 2 is a fragmentary view taken in the direction of the arrow 2 of Fig. 1.

Fig. 3 is a side or end elevation of the dredge equipped with a static-fluid operated prime mover, with bail broken away and control means not shown.

Fig. 4 is a plan view of Fig. 3.

Fig. 5 is an enlarged section through the sealing means for the bucket and corresponds to a section taken on line 5-5 of Fig. 1.

Fig. 6 is a fragmentary end elevation showing part of the dredge of Figs. 3 and 4, with one type of prime mover control which is controlled through cooperation with a surface.

Fig. 7 is a fragmentary front elevation of Fig. 6'.

Fig. 8 is an enlarged fragmentary vertical section through the static-liquid operated prime mover with hoisting cable controlled prime mover control.

Fig. 9 is an enlarged sectional elevation through the fiuid operated prime mover and control therefor, utilizing the pressure of external fluid as the control medium.

Figs. 1 and 2 show the simplest form of the invention which consists of a standard clam shell bucket and an electric motor mounted directly thereon and operating the bucket through a gear train. This. type is most suitable for unsubmerged operation, and also for submerged operation when the depth of subinergence is not sufl'icient to provide the necessary pressure for operating the fluid actuated prime mover.

The clam shell bucket consists of a bi-valve or two scoops -I0 and I I, each of which have ends I2, bottom l3 and top M, the two scoops being hinged together as shown at l5, and having digging teeth l6 integral with or secured to the lips or bottom edges.

The side and bottom edges of the cooperating valves or scoops are provided with cooperative sealing means, indicated at 5, the respective sealing members being indicated at I! and I8, and which extend throughout the length of the side and bottom edges. This sealing means is shown in detail in Fig. 5, and will be fully described in connection with that figure.

While the dredge or bucket is digging into the muck -or sludge, it is necessary to permit water to escape through the top of the bucket, and while the bucket is being hoisted to the surface,

- it is necessary to prevent all ingress of water to the interior of the bucket. For this purpose, a flap valve I9 is provided, which permits passage of water from the interior of the bucket during closing and digging, and seals the bucket against ingress as the bucket is raised to the surface, since the dynamic pressure will hold the valve tight on its seat.

Mounted on the scoop III is a motor housing 29 including an integral worm and worm-wheel housing 2| the entire housing being sealed against external pressure, as by packing means 22 about the worm-gear shaft, which are the only points which require packing with the exception of the conductor passage, which is sealed by the plug 221 in which the conductors are sealed.

Mounted within the housing 20 is an electric motor 23, on the shaft 24 of which is mounted a worm 25, which cooperates with a worm-wheel 26, this worm-wheel being fixed on the shaft 21, the housing 2| having integral bearings 28 and 29 and spaced bearings 30 and 3| for the shaft 21.

Fixedly mounted on each end of shaft 21 are the respective pinions 32 and 33, which mesh with the respective sector gears 34 and 35 which are fixedly secured to the respective ends I2 of the bucket II as indicated at 36. A bail 31 is mounted on the pintle shaft 38 for connection tov a hoisting cable, (not shown).

A recess 39 is formed in the top of the scoop II to receive the worm-gear housing 2|, and coaxial recesses 49 and 4| receive the shaft 21 and bearings 28 to 3| when the bucket is opened.

Sealing means for the edges or jaws of the bucket is shown in section in Fig. 5, and consists of the bottom and side encompassing jawsdneluding for one scoop, the male member 42, and for the other scoop, the female member 43, the male member having an integral divergent member 44 which cooperates in the closed position of the bucket with a pneumatic insert 45 secured in the female member, this insert consisting of a rubber or other impervious resilient tube retained in a recess 46, one portion 41 being of considerable thickness to form a cushion and reinforcement for the member 44. This tube is inflated with air under a predetermined pressure, which pressure is maintained at a normal by the spring 48 acting on the piston 49, which operates in a cylinder 59 having a fluid inlet 5|.

The piston is directly connected to a smaller piston 52 which operates in a second, coaxial cylinder 53, this cylinder 53 communicating with the tube 45 through a duct or tube 54.

Thus, as the external pressure is increased, as by lowering the dredge into water, the pressure of the water acting on piston 49 amplifies the pressure in the tube to a value greater than the existent surrounding pressure, making the seal effective irrespective of any external pressure.

The motor may be manually controlled in conjunction with overload switches from the hoisting base, (not shown), or may be automatically controlled by any of the various means shown in the various views.

As shown in Fig. 1, current is brought into the motor housing from a supply through conductors 55 and 56, and switch means is incorporated in the worm gear housing, and consists of a double ended spring contactor 51 mounted on, and insulated from the housing 2|, and two cooperatively related spring contacts 58 and 59 insulated from each other and from the conductor 51 and respectively connected through conductors 69 and 6| to one conductor 55 and to the motor 23, an insulating pin 62 on the worm gear being cooperatively related to the contact springs 58 and 59.

Mounted on, or integral with the housing 2|, is a cylinder 63 having a fluid inlet 64, and a piston 65 has a piston rod 66 which is cooperatively related to one end of the conductor 51 and is urged outwardly by the spring 61. A manually operable lever 68 is cooperatively related to the other end of spring contact 51.

When the dredge bucket is open, pin 62 is in the opposite position from that shown and in contact with the contact 58, holding contact 58 away from contact .51 and maintaining this broken contact until the bucket is lowered to a .62 contacts and forces contact 59 out of contact with 51, breaking the circuit with the bucket closed and locked by the worm and worm wheel.

As the dredge is raised to the surface, the pressure on piston 65 is reduced and the piston 65 and rod 66 are retracted, permitting the switch elements 51 and 58 to return to their normal position, the normal position of contacts 51-58 and 51-59 being closed or complete. Thus, the circuit remains broken only between 51 and 59.

When the bucket is to be opened and dumped, the lever 68 is manually moved to force contact 51 into cooperation with contact 59, starting the motor, .pin 62 leaving contact 59 and permitting it to return to normal or closed position to contact 51.

In Figs. 3 and 4, and 6 to .9 are shown a fluid operated dredge and various types of control means therefore, which dredge may be operated by any fluid under pressure, or by the static pressure of a liquid of submergence, such as by operation by water in which the dredge is submerged. This type is particularly desirable in connection with deep-sea dredging, since no power is required for closing and opening of the bucket, the only power required being for hoisting, and even this power is reduced due to the buoyancy of the transfer tanks.

In these modifications, the bucket is modified by being divided into two scoops 69 and 10 with intervening mounting platform for the prime mover, as shown at 1|, the scoops being hinged to the platform as shown at 12 and 13.

Mounted on platform 1| is a cylinder 14 in which operates a piston 15 having a piston rod 16 to which is attached a cross head 11, which terminates at its opposite ends in depending racks 18 and 19 which selectively and simultaneously cooperate with gears 8IJ-8I and 82-83, which gears are fixed on the rocker shafts 84 and 85, suitable bearings being provided for these shafts, as shown, and indicated at I56 and I51.

Fixed on the opposite ends of shafts 84 and 85 are cranks 86, 81, 88 and 89, which are operatively connected to the respective scoops 69 and in through links 90, 9|, 92 and 93, these links being hingedly connected to the bearings 94, 95, 96 and 91, which are secured to the respective buckets.

Additionally mounted on the platform or base ii is one or more air receivers 98, the receiveri or receivers being in communication with the upper part of the cylinder 14, as shown at 99, the receivers 98 forming fluid transfer means to diminish the pressure reacting in the cylinder below the natural value created through compression as the piston is forced upwardly by the liquid of submergence. This air under pressure is used during transfer in the return stroke for initially opening and assist the counter-weights I and IOI in fully opening the scoops.

The control shown in Figs. 6 and 7 is suitable for controlling operation of the motor in Fig. l, in connection with an overload relay or circuit breaker, or in connection with the means shown in Fig. 1, by providing an electric switch in place of the valve shown.

As shown, this control is adapted for control of the fluid operated prime mover. The shoe I02.

is curved upwardly at both ends, and pivotally attached to the drop bar I03 as shown at I04, at a point removed from the longitudinal center of the shoe to create a difference in length of the two ends to cause the shoe to pass substantially edgewise through the water during descent to prevent operation until an actual surface of non-liquid material is encountered, the curved ends I05 and I06 causing the shoe to seat when contacting a sub-surface I01.

A shoulder I00 on the drop bar limits the drop thereof, and the upper end of the bar cooperates with a lever I09, which may be made to operate an electric switch for the motor, or, as shown, operates a valve IIO. This lever is normally maintained in lowered position through the medium of a spring III, or counterweight, (not shown).

The water of submergence is delivered or admitted to the cylinder 14 through the pipe II2, the terminal II3 of the valve functioning as inlet during closing of the bucket, and as discharge during opening of the bucket.

When the bar is in dropped position, as shown, the shoe I02 will contact the sub-surface I01 in advance of the bucket, and as the bucket is lowered further, the bearing II4 slides down on the bar. The bar raising lever I09, opening the valve and admitting water to the cylinder 14,

which forces the piston 15 up to the top of its stroke, coincidently drawing the racks 18 and 19 up between the gears 80-8I and 8283,- rotating shafts 84 and 85 and cranks 86-81, 8889,fr0m the dotted position I I5-I I6 to the full line position 8681, closing the bucket from the dotted position Fig. 3, or full line position Fig. 6 to the full line position shown in Fig. 3.

As the hoisting cable I I1 lifts the dredge from the subsurface, the bar I03 drops, permitting lever I09 to close valve IIO through the medium of spring I I, entrapping the liquid in the cylinder 14, looking the bucket in closed position.

As the piston is forced upwardly by the admitted fluid, the air above the piston is transferred through the bypass 99 to the air receiver 93, thus diminishing the normal pressure of compression while increasing the differential pressure between the opposite sides of the piston.

When the bucket is to be dumped, lever I09 is raised manually to the dotted position to permit escape of the fluid or water from the lower end of the cylinder, the air under slight compression in the transfer tank 98 being transferred back to the cylinder and assisting the counterweights I00 and MI in opening the bucket and forcing the water out of the cylinder. When the bucket is fully opened and the water all drained from the cylinder 14, the lever I09 is released, closing the valve H0 and locking the .bucket in open position; 7

In Fig. 8, another control means is shown for automatic control of the bucket and prime mover. In this modification, the hoisting cable I I I is connected to a plunger or slide II8 which is slidable in a bearing II9 formed in the bail I20. This plunger cooperates with a counterweighted lever I2I which is pivotally mounted at I22 on the hail, the counterweight I23 normally maintaining the lever in contact with the underside of plunger II8, as shown.

The end I24 of lever I2I has pivotally connected thereto a connecting rod I25 which connects to valve lever I26. Thus, as the bucket encounters the subsurface I01, the hoisting cable is naturally slacked off, permitting the plunger II8 .to drop, depressing lever I2I and opening valve I21, admitting water to cylinder 14, and operating in the manner previously described. When the hoisting cable is again drawn taut for hoisting, the plunger is drawn up, permitting the valve to close. Lover I2I may be connected directly to the plunger, if desired.

The two controls just described depend on the dredge contacting a subsurface for operation, and in both types, the bucket is hydraulically locked in both, closed and open position of the bucket.

Fig. 9 shows a depth control for the prime mover, which is particularly suitable for control where the subsurface is very sludgy. or where samples are to be taken at various depths, and since efiicient sealing means is provided for the bucket, this control can be used for taking water samples at various depths. It is also suitable for dredging. by first ascertaining the. depth of the water at the point to be dredged.

A through piston rod is shown to illustrate one method of equalizing the pressure, to prevent the unbalanced pressure on the piston rod from prematurely closing the bucket. Suitable hydraulic packing is provided as indicated at I20 and I29. All bearings exposed to the water of submergence are efficiently packed, but which packing does not form a part of this invention.

The control, Fig. 9, consists of a hydraulic control and a valve actuator, which are mounted on, or integral with, the cross-head 11, being carried on an arm I30.

The hydraulic control consists of a cylinder I3I having a piston I32 urged by a spring I33 which seats against an adjustable seat I 34, the spring I33 being adjusted as to tension for depth by means of the screw I35, the adjustment being made for the depth at which the bucket 69-10 is to be closed.

An intake passage I36 is formed in the bottom of the cylinder, and an outlet I31 is normally closed by the piston, and communicates with the valve actuator cylinder.

The valve actuator consists of a cylinder I38 having a piston I39 and a through piston rod I40, which has a through axial bore in which the actuator rod MI is slidable, and which is provided with an integral collar I42 and a head I43.

The upper end of the piston rod I40 has a head I44, a spring I45 cooperating between the head I44 and the top of the cylinder to normally maintain the piston I39 in its highest position in the cylinder I38.

A flexible conduit I46 communicates between the bottom of cylinder I38 and air transfer receiver 98; and another flexible conduit I41 communicates between the upper end of cylinder I39 and valve I49, this valve having'an intake and discharge I49 communicating with the lower end of cylinder 14 through a pipe I50. A spring II is mounted on rod I4I for cooperation between the heads I43 and I44 to permit manual unloading of cylinder I4 for opening the bucket.

The operation of this control is as follows:

Screw I35 is first adjusted for the depth at which the bucket is to be closed. As the dredge is lowered into the water I52, the pressure of submergence gradually increases, water acting through the port I35 on piston I32 against spring I33, gradually raising the piston I32 to finally uncover the port I31, water then passing through port I36, cylinder I3I, passage I31 into cylinder I38, depressing piston I39.

As the piston I39 is depressed with its piston rod, against the action of spring I45, the lower end of the piston rod cooperates with the collar I42, forcing rod I4I down and moving valve lever I53 from the dotted position to the full line position, opening the valve I54 and admitting water of submergence to the lower part of the cylinder 14 through passage I50, while also permitting equalization of pressure through conduit I41, entrapped air in the lower part of cylinder I33 having been transferred to receiver 99, and entrapped air in the upper part of cylinder 14 having also been transferred to cylinder or receiver 98.

As the piston I5 raises, the piston rod 16 and cross-head II coincidently raise the control and actuator. After predetermined travel of piston rod IS, the head I44 cooperates with spring seat I55, the final movement of the piston raising rod HI and lever I53, closing valve I54, hydraulically locking piston I5 at the top of its stroke with the bucket closed.

As the dredge is raised, the external pressure is reduced and piston I32 lowers and closes port I31, locking piston I39 in its lowest position.

When the bucket is to be opened for dumping, lever I53 is manually pulled down from the dotted position against the action of spring I5I and the water is drained from the lower end of cylinder 14, and through conduit I41 and passage I31, (which is now uncovered by the top of the piston I32), draining the water from the spring housing section of cylinder I3I and from the upper end of cylinder I38, counterweights I00 and IIII, assisted by the return transfer of the air under slight pressure in transfer receiver 98, and spring I45 returning all parts to normal position with the bucket open, and hydraulically locked in open position, the lever I53 returning to the dotted position automatically when released and closing the valve I54 and sealing the lower part of the cylinder I4.

The clam shell bucket may be of any type in which cooperative scooping elements are employed. The seal for the scooping means may be of any type which is self compensating for variations in external pressures and which will build up its resistance as the pressure is increased, always at a value greater than the external pressure.

The simplest operative connections are shown between the prime mover and the dredge, and the static liquid operated prime mover may be adapted for operation of any type of device to be used in any case where external fluid pressure is available in a free state such as for deep-sea dredging.

It will be understood that variations in construction and arrangement of parts, which variations are consistent with the appended claims, may be restorted to, without detracting from the spirit or scope of the invention, or sacrificing any of the advantages thereof.

I claim:

' 1. In combination, scooping means having cooperative scooping elements, a prime mover mounted on said scooping means, an operative connection between said prime mover and said scooping means, and cooperative sealing means on the respective scooping elements, and means building up the internal resistance of said sealing means as the external pressure is increased, to a value greater than the external pressure.

2. In combination. a submersible device and a prime mover mounted thereon and operated through the medium of fluid in which said device and prime mover are submerged, pressure-controlled means controlling operation of said prime mover for one operation of said device, and manually controlled means controlling operation of said prime mover for another operation of said device.

3. In combination with a clam shell bucket or the like, sealing means for the cooperative edges oi said bucket comprising a resilient element mounted in one cooperative edge for cooperation with the other cooperative edge, and means actuated through the medium of surrounding liquid under pressure maintaining the internal resistance of said resilient element at a value greater than said external pressure.

4. A submarine dredge comprising a clam shell bucket having cooperative scoop elements; a cylinder mounted on said bucket, a piston and piston rod for said cylinder; operating means connecting said piston rod with said scoop elements; a valve for controlling admission of water of submergence to one end of said cylinder; means opening said valve when said dredge has been submerged to a predetermined depth and closing said valve during hoisting of said dredge.

5. A submarine dredge comprising a clam shell bucket having cooperative scoop elements; a cylinder having a piston and piston rod and mounted on said bucket; operating means connecting said piston rod with said scoop elements; a valve controlling admission of water in which said dredge is submerged, to one end of said cylinder; a receiver in communication with the other end of said cylinder for transfer of fluid; me'ans opening said valve when said dredge has been submerged to a predetermined depth and depth adjusting means therefor, said means closing said valve when said dredge is hoisted to a lesser depth, and manually operated means operable at will for discharging admitted water from said cylinder, said transfer fluid acting to open said bucket as the water is discharged, and counterweight means assisting in the opening of said bucket, said bucket being fluid locked in both its open and closed positions.

6. A submarine dredge comprising; scooping means having cooperative scooping elements; a fluid-actuated prime mover mounted on said scooping means; an operative connection between said prime mover and said scooping means for opening and closing said scooping means; and submergence controlled means controlling admission of fluid of submergence to said prime mover for operation thereof at a predetermined depth or submergence.

7. A structure as claimed in claim 6; cooperative sealing means on the respective scooping elements for sealing said scooping means when in closed position against escape of sludge, the sealing means on one of said elements being formed of resilient material; and means actuated by fluid of submergence building up the internal resistance of said resilient material to a value greater than the fluid of submergence to maintain said resilient sealing means effective against its external fluid pressure.

8. A structure as claimed in claim 6; said submergence controlled means comprising; a valve and valve control means mounted on said dredge; said valve control means being fluid-actuated under a predetermined depth of submergence opening said valve for admission of fluid of submergence to said prime mover for closing said scooping means and closing said valve as said dredge is raised to a lesser depth of submergence for hydraulically locking said scooping means in closed position; said control means including manual control means for opening said valve to drain fluid of submergence from said prime mover after said dredge has been removed from said fluid of submergence.

9. In a device for submarine operation; a fluidoperated prime mover; a valve controlling passage of fluid ofsubmergenoe to and from said prime mover for actuation thereof; and valve control means mounted on said device and actuated under a predetermined head of submergence opening said valve for passage of fluid of submergence to said prime mover for operation thereof and closing said valve as said device is raised to a lesser head of submergence for hydraulically locking said prime mover against further operation.

10. A structure as claimed in claim 9; said control means including manual control means for opening said valve to drain fluid of submergence from said prime mover after said device has been removed from said fluid of submergence.

11. In a device for submarine operation, a fluidoperated prime mover; valve means and control means therefor operated through the medium of fluid of submergence when said prime mover has been lowered into said fluid of submergence to a predetermined depth, admitting fluid of submergence to said prime mover for operation thereof and sealing admitted fluid in said prime mover when said prime mover is raised to a lesser depth to hydraulically lock said prime mover against further or retrograde operation.

12. In a device as claimed in claim 11; hand operated means for operating said means when said prime mover has been removed from said fluid of submergence for draining admitted fluid from said prime mover for a subsequent fluid of submergence operation of said prime mover and means returning said hand operated means to its initial position when manually released, for subsequent fluid of submergence operation of said means operated.

13. In a device as claimed in claim 11; a receiver in communication with said prime mover and mounted on said device and forming transfer means for transfer of prime-mover-contained fluid as fluid of submergence actuates said prime mover.

14. A submarine dredge comprising; a fluid-operated prime mover; valve means and control means therefor actuated upon cooperation of said dredge with a sub-sea surface to open said valve to admit fluid of submergence to said prime mover for operation thereof and releasing said valve to close when said dredge is raised out of cooperation with said sub-sea surface to lock contained fluid in said prime mover to prevent retrograde operation thereof, and including means closing said valve when released.

15. A structure as claimed in claim 14; and a breather chamber in communication with said prime mover for gas displaced in said prime mover through fluid of submergence operation thereof, for maintaining reactive pressure in said prime mover at a low value.

16. A structure as claimed in claim 14; and manually-controlled means associated with said valve and operable at will when said dredge is removed from said fluid of submergence for opening said valve for draining admitted fluid from said prime mover; said means closing said valve also acting to close said valve when said manually-controlled means is released.

17. A structure as claimed in claim 14; said dredge including cooperative scooping elements and operative connections between said prime mover and said scooping elements; and counterweight means associated with said scooping elements urging said scooping elements to open.

18. A structure as claimed in claim 14; said dredge including cooperative scooping elements and operative connections between said prime mover and said scooping elements; counterweight means associated with said scooping elements urging said scooping elements to open; manually controlled means associated with said valve and operable at will when said dredge is raised from said fluid of submergence for opening said valve for draining admitted fluid from said prime mover to release said scooping elements to open, said means closing said valve also acting to close said valve when said manually-controlled means is released, to lock said scooping elements in open position and prevent operation of said prime mover while being lowered to said sub-sea surface.

JOHN C. WILLIAMS. 

